1. Field of the Invention
The present invention relates to a paper sheet separation and transfer apparatus which separates a plurality of stacked paper sheets such as postal matters, bills and plain-paper copies, one by one, and takes each sheet out onto a transfer path.
2. Description of the Related Art
As a conventional paper sheet separation and transfer apparatus, a separation and transfer apparatus having a separation unit to prevent overlapped paper sheet feeding has been known. (For example, refer to Jpn. Pat. Appln. KOKAI Publication No. 2003-81463.) This separation and transfer apparatus has a take-out roller which rotates and contacts a paper sheet at one end of a stack, and takes it out onto a transfer path, and a transfer path which transfers the taken-out paper sheet. On the transfer path of the downstream side of the take-out roller, a separation unit and a transfer unit are arranged close to each other along the paper sheet take-out direction.
The separation unit has a feed roller which contacts the paper sheet taken out onto the transfer path on the same side as the take-out roller and rotates forward, and a separation roller which is located opposite to the feed roller through the transfer path and separates second and subsequent paper sheets taken out together with the first sheet by giving them a reverse force (a tangential force).
The transfer unit has a drive roller which accepts the transfer direction end of a paper sheet passed through a nip between the feed roller and separation roller, and rotates forward, thereby pulling out the paper sheet from the nip of the separation unit and feeding it, and a pinch roller which is arranged opposite to the drive roller through the transfer path.
In the separation and transfer apparatus with the above structure, when stacked paper sheets are taken out onto the transfer path, the take-out roller is rotated first, and a paper sheet at one end of a stack is taken out onto the transfer path. In this case, by the friction between paper sheets, second and subsequent paper sheets may be taken out together with the first paper sheet. The taken-out second and subsequent paper sheets are separated by the separation unit, and transferred to a processing unit in a later stage through the transfer path.
The separation unit feeds forward the preceding first paper sheet by the feed roller, and rotates the separation roller in the reverse direction contacting the second and subsequent sheets overlapped with the first sheet, and separates these second and subsequent paper sheets by pushing them in the reverse direction.
However, in the above conventional unit, if the take-out roller takes out two paper sheets with different size and thickness, overlapped paper sheets may not by completely separated by one separation unit.